/Engine/Source/Runtime/CoreUObject/Public/Misc/PackagePath.h
The reported array will be length 1 for every case except EPackageSegment::Header and HeaderExtension == EPackageExtension::Unspecified, in that case it will be the list of all enumerated header extensions
ATArrayof EPackageExtensions. If the array contains EPackageExtension::Custom, caller must call GetCustomExtension to get the specific string.
TConstArrayView< EPackageExtension > GetPossibleExtensions ( EPackageSegment PackageSegment ) const